Synchronizing device



Dec. 18, 1951 v| scHMlD 2,578,747

` SYNCHRONIZING DEVICE Filed March 4, 1948 O wf q 's l o? V u gs j f N Oy f i ,4%

O s l 's R m is l Q u .p mi "5 a of w@ I 5|@ m 1u N *5 O o mvENmRATTORNEYS q Y@ Mg/Mr@ Patented Dec. 18,v 1951 OFFICE SYNcHaoNIzINGDEVICE Leopold Schmid, Gmuna, -Karnten,Austria Application March, 4,1948, Serial No. 12,946

Y `In Austria March 13,1947

This invention relates to synchronizing device.

An object of this invention is to provide an,

improved transmission of the above type constructed' and arranged toaccomplish the synchronizing operation inless ltime than'has heretoforebeen customary.

' vA further object is to provide such a transmission with an improvedsynchronizing device which accomplishes the synchronizing operationwithout having to vary the angular velocity of heavy parts. Y

A further object is to provide a constant-mesh transmission with asynchonizing device of such construction and arrangement that thesynchronizing surfaces are engaged only during the gear-shiftingoperation and are disengaged upon completion thereof.

A further object is to provideu a relatively simple inexpensivesynchronizing device for transmissions of the above type.

Other' objects will become apparent from the following description takenin connection with the attached drawings showing two illustrativeembodiments of the invention and wherein Fig. 1 is a longitudinalsection through a three-speed and reverse transmission having asynchronizing mechanism' constructed in accordance with one embodimentof this invention. Fig. 2 is a tra-nsverse sectional view on the line2-2 of Fig. 1, and Fig. 3 is a partial view, similar to Fig. 1, showinganother modication of the invention. I

In the present invention a. gear-shifting or actuating member forms onehalf of a jaw clutch and consists of a slidable sleeve splined' to thetransmission power shaft and provided with a toothed periphery, which isdisposed between annularV synchronizing members, the arrangement beingsuch that, when shifting gears, iirst a synchronizing member and thenthe clutch teeth arejihrought into engagement withcorresponding-ly-tothed bores of the transmission'gears which form theother half of the .iaw clutchfor connecting an associated gear to thepower shaft. Bythis means synchronized rotation of the shaft and therespective gears is obtained without providing a synchronizing mechanismon each individual speed gear. However, it is also possible, bysacricing this advantage, to provide thefslidng sleeve with clutchteeth,A only, in which` case synchronizing members areV provided on; 'yach speed gear so that, on shifting gears, the teethpn the sleeve rstengage such members and then the clutch teeth formed in the bore of thegear. In both constructions the weight-of the transmission parts to beaccelerated or re- 6 Claims. (Cl. 192--53) tarded during gear shiftingis reduced to a minimum.V

A further considerable advantage is that the gear shift is brought aboutsimply by the axial displacement of the sleeve, whereby the selectiveshifting of the gears wtih movements of an operating :lever in diierentdirections is done away with. This advantage is especially noticeable inthe case of rear engines.

Tests have shown that the shortest time taken for gear changing hithertowith synchronizing arrangements, namely 0.4 second, is reduced'to from0.1 to 0.2 second.

Referring to the drawings, in the casing I is the suitably supporteddriving shaft 2 provided, for instance, with asplined section 3. On thisshaft is mounted so as to be longitudinally slidable thereon and coupledto the shaft,` so as to turn with it, a jaw clutch member 4 which in theexample shown iS made in one piece with and actuating, sliding sleeve ordriving member 5.

Each individual speed gear 6 has a central bore 'I'and is supported inanti-friction bearings 9 in ribs 8 of the casing, which extend betweenthe gears. The bearings are mounted between openings ID in the casingribs and the hub bodies II of the gears. A

The jaw clutch member 4 has friction surfaces which as shown in Fig. 1consist of synchronizing members arranged on each side of the clutchmember proper located in grooves I2 and I3. They consist of rings I 4,I5 which are slotted and radially yieldable. The rings I4, I5 aresecured against turning b ya part I6 which has the form of an annulussector andis fixed by means of pins I 1, I8 to the. actuating or drivingmember 5. In order to enable the synchronizing rings to spring freely,clearance is provided between the part I6 and the ring ends.

Each of the gears 6 has internal jaw clutch teeth I 9 which during thegear-changing operation irst coact with one of the synchronizingmembers, so that both act as friction surfaces and thereby as asynchronizing coupling. By this means the velocity of the associatedgear is synchronized with that of the clutch member 4. permittingengagement of the clutch member with the clutch teeth I9 of the gear. Inorder still further to shorten the operative motions for changing thespeeds the internal clutch teeth I9 can be locatedat the axial edge ofthe gearin the internal bore.

On the driven shaft 20 are keyed the gears 2l which are in permanentmesh with the gears 8. In order to hold the actuating member in eitheroperative or idle running positions, the driving shaft 2 has atransverse bore 22 with two detent balls 24 forced apart by a spring 23for axially securing the sliding sleeve by means of the recesses 25.

The transmission has very few parts, is therefore cheap to manufactureand takes up very little space. When changing to any of the speeds, theonly'parts the speed of revolution-of which must be altered, are theclutch disk (not shown) on the driving shaft, the driving shaft 2 and2,578,747 f i i the actuating member A with the sliding sleeve f i.siongear means provided with internal clutch teeth for different speedsand adapted to be oper- 5. The transmission thus has the smallestsynchronizing masses which are at all possible. Gear shifting iseffected only by motion parallel to the driving shaft, through the,engagement of a shifting fork in the groove 26 of the sliding sleeve 5.

Between each operative position is an idlel running position. In 1 theactuating member -is shown in one of these idle running positions. Amain idle running position may be provided between two speeds throughallowing a greater distance between two successive speed gears 4and willpreferably be placed between the forward and reverse gears.

Amodied construction of the invention is shown in Fig. 3 in whichsynchronizing rings 21 and 28 are provided on both sides of the internal-clutch teeth 29 of each individual speed gear 30. Infthis instancethere are no synchronizing members on the actuating member 3|. Duringthe gear-shifting operation the clutch teeth on the actuating lmember 3|frictionally engage a synchronizing ring 21 or 2,8 Ybefore meshing lwiththe clutch teeth 29v on the gear 30 resulting in synchronized rotationof the gear and the actuating member prior to engagement of the clutchteeth. According to the invention it is, of course, also possible to,provide for some, only, of the gears to be synchronized. Instead ofthere being only onesynchronizing membervson each side of theinternalgteeth ofthe gear or actuating member several synchronizingmembers may be provided oneach side. Two or more actuating members maybeprovided each of which actuates only some of the speeds. Othervariations Will be obvious.

The invention is not intended to be limited to the two forms shown,which are to be understood as illustrative, only, and not as limiting,as various changes in construction and arrangement may be made,allcoming withinv the scope of the 'following claims;

What is claimed is: ril. In a constant mesh variable speed powertransmission mechanism, a rotatable driving member mounted for axialsliding movement, a series of rotatable selectively driven membersmounted coaxially with said driving member and spaced from each other inan axial direction, the driving member being formed with outwardly ex'-tending driving teeth .and each of the driven members being formedwitiiinwardly extending teeth complementary to said outwardly extendingteethon the driving member, the inner ends of which teeth on the drivenmembers being con# centric with the axis of the driving member wherebythe driving member may engage` with one of the driven members to rotatethe same, together with two friction members mounted on the drivingmember, lone on each side ofthe teeth-thereon, `saidrfriction membershaving an Outer surfacegenerally vconcentric withithefaxescithe drivingand ,drivenV members and slightly larger in diameter than the ends ofthe inwardly extending teeth on the driven members, whereby, as thedriving member is shifted axially past any of the driven members in theseries, one of said friction members will first engage with the ends ofthe teeth on the one of driven members to synchronize the speed of thedriving member and then the teeth on the drivingmembervwill positivelyengage the teeth on said. driven member.

2. In a constant-mesh variable speed trans- Vmission mechanism, a driveshaft and transmis- -ated by lsaid shaft, a cooperating clutch membersplined tosaid .shaft for movement longitudinally 'f thereof past vanyof the means, said clutch member having clutch teeth adapted to be movedinto and out of mesh with the selected clutch teeth on said gear means,a radially resilient synchronizing ring mounted on said member `on each-side of the clutch-teeth of the cooperating `clutch member, each ringhaving a friction surface forv yieldingly engaging .va surface ,von .theclutch teeth of saidother means upon movement of said clutch memberlongitudinallyV of said shaft, to frictionally precouple said means andsynchronize the angular velocities thereof, whereby said clutch member'canv be moved into clutching lengagement with said-gear means fromeither side thereof longitudinally of said shaft.

3. In a geared -power transmission mechanism a drive shaft, Va pluralityof spaced transmission gears forming a series. for imparting differentspeeds, each gear having internal teeth adapted to receive their speedfrom the drive shaft, a cooperating clutch lmember mounted on the shaftandlongitudinally movable thereon, said clutch member being concentricwith the gears and being adapted selectively to move telescopically intoandout of `mesh with the internal teeth on the transmission gears, aradially resilient annular synchronizing memberI mounted on either sideof said clutch member, having `a friction surface foryieldingly'preengaging a surface on the internal teeth of the selectedtransmission gear when said clutch member is moved on said drive shaft,-and means fixing the synchronizing member to the clutch member forresisting relative rotation of its ring thereon so that upon movement ofvsaid clutch member longitudinally of said shaft said synchronizing ringfrictionally precouples said members to synchronize the .an--l gularvelocities thereof prior to meshing of said Clutch teeth.

4. In a constant-mesh variable speed power transmission mechanism, apower drive shaft, a splined actuating sleeve movable longitudinally onsaid shaft having a vpositive clutch element thereon, aseries ofindependently rotatable gear members lmounted in spaced relation aroundand longitudinally of the sleeve having internal teeth adapted forselective clutching with said positive clutch element to producedifferent speeds in the mechanism, an expandible annular member on thesleeve disposed on either side of. said clutch element for frictionallyand selectively precoupling said positive 'clutch element to each gearto synchronize theselected gear and clutch element; and actuable meansin connection with the sleeve for moving the.l sleeve successively pastsaid gear members to synchronizev and clutch the selected gear-memberwiththe positive clutch element.v i

5. In a geared power transmission mechanism, a rotatable driving membermounted for axial sliding movement, a series of rotatable selectivelydriven members mounted coaxially with said driving member and spacedfrom each other in an axial direction, the driving member being formedwith outwardly extending driving teeth and each of the driven membersbeing formed with inwardly extending teeth complementary to saidoutwardly extending teeth on the driving member, the inner ends of whichteeth on the driven members are concentric with the axis of the drivingmember whereby the driving member may engage with any one of the drivenmembers to rotate the same, said driving members further having acompressible friction member adjacent the teeth on the driving member,said friction member having an outer surface concentric with the axis ofthe driving and driven member and slightly larger in diameter than theends of the inwardly extending teeth of the driven members, whereby asthe driving member is shifted axially the friction member will engagewith the ends of the teeth on the selected driven member to synchronizethe speed of the driving member and then the teeth of the driving memberwill positively engage the teeth on the selected driven member, saiddriving mem ber being adapted to move successively past said drivenmembers to synchronize the selected driven member.

6. In a constant-mesh variable speed power transmission, a drive shaftand a series of successive coaxial transmission gear members providedwith internal clutch teeth adapted to be connected to said shaft fordiierent speeds, a cooperating axially movable clutch member mounted onsaid shaft disposed interiorly of the internal clutch teeth and havingclutch teeth adapted to successively mesh with the clutch teeth on theselected gear member in the series, and slotted, yieldable means mountedon the clutch member providing a resilient friction surface on one ofsaid members positioned to initially yieldingly and frictionallypreengage a surface on the clutch teeth of said other member tosynchronize the angular velocities of said members prior to meshing saidclutch teeth, said resilient friction surface being movable out ofclutching engagement to inoperative position upon subsequent meshing ofsaid clutch teeth, said slidable clutch member being adapted to movelongitudinally past one selected gear member to another in the seriesfor varying speed. LEOPOLD SCI-IMID.

REFERENCES CITED The following references are of record in the le ofthis patent:

UNITED STATES PATENTS Number Name Date 1,511,232 Murray Oct. 24, 19241,828,508 Murray Oct. 20,v 1931 1,924,875 Murray Aug. 29, 1933 1,957,416Weydell May 1, 1934 2,048,883 Murray July 28, 1936 2,416,154 ChiltonFeb. 18, 1947

